Downhole pump assembly having engines spaced apart by a production pump

ABSTRACT

A fluid actuated pump assembly having a valve assembly, an engine means, and a production pump. The engine means is comprised of an upper and lower engine assembly with the pump being interposed therebetween. A flow passageway formed from the valve assembly through an axial passageway in the upper engine assembly, through an axial passageway in the production pump, and to the lower engine assembly provides a power fluid source and exhaust to the lower engine. Another flow passageway is located externally of the piston of the upper engine and provides a second flow passageway which is connected to the upper engine assembly so as to enable power fluid and spent power fluid to flow to and from the upper engine. This expedient causes the pump piston to be actuated by a compressive force which is applied to each of the connecting rods attached thereto.

United States Patent [151 3,60,640

Roeder I 1 Mar. 211, 1972 [54] DOWNHOLE PUMP ASSEMBLY HAVING ENGINES SPACED APART BY 'y EXaminerR0bert lk r A PRODUCTION PUMP Attorney-Marcus L. Bates [72] Inventor: George K. Roeder, Box 4335, Odessa, [57] ABSTRACT 79760 A fluid actuated pump assembly having a valve assembly, an

[22] Filed: May 11, 1970 engine means, and a production pump. The engine means is Appl. No.: 36,351

U.S. Cl ..4l7/396 comprised of an upper and lower engine assembly with the pump being interposed therebetween. A flow passageway formed from the valve assembly through an axial passageway in the upper engine assembly, through an axial passageway in the production pump, and to the lower engine assembly provides a power fluid source and exhaust to the lower engine. Another flow passageway is located externally of the piston of the upper engine and provides a second flow passageway which is connected to the upper engine assembly so as to enable power fluid and spent power fluid to flow to and from the upper engine. This expedient causes the pump piston to be actuated by a compressive force which is applied to each of the connecting rods attached thereto.

10 Claims, 9 Drawing Figures Patented March 21, 1972 2 Sheets-Sheet 1 2;} EF 27 as 28 23 ll 2 2o 19 30 2s ,asra E42. 223

J VENTQR, GEORGE K .KOEDER.

MARCUS L BATES H/S FIGENT Patented March 21, 1972 2 Sheets-Sheet 2 H/S HGEN T ZNVE/VTOR GEORGE KROEDER MARCUSLBATES DOWNIIOLE PUMP ASSEMBLY HAVING ENGINES SPACED APART BY A PRODUCTION PUMP BACKGROUND OF THE INVENTION Reference is made to my copending patent application Ser. No. 790,591, filed Jan. 13, 1969; now U.S. Pat. No. 3,540,814, issued Nov. 17, 1970 and to the various prior art cited and set forth therein.

In the pump of my above mentioned prior patent, it has been found expedient in deep wells to use connecting rods fabricated from material which exhibits an elastic limit when in compression which exceeds the elastic limit of the metal when in tension by more than a two-to-one ratio. For example, design engineers realize that some hardened metals exhibit and ultimate strength when in tension as low as 20,000,p.s.i. as compared to 90,000 p.s.i. when placed in compression. On the other hand, materials such as structural steel exhibit the same ultimate strength in both tension and compression. Accordingly, as one utilizes materials of construction from a wear rather than a strength viewpoint, the tensile strength accordingly is diminished. In fabricating the pull rod of my previous patent for use in deep wells, the pull rods often break when fabricated from certain hard metals. Accordingly, it would be desirable to provide a downhole pump assembly having a pump piston which is actuated by an engine which pushes rather than pulls a pump piston in order to take advantage of metals which exhibit low tensile strength but which exhibit great compression strength. This expedient would provide a slim hole pump having a maximum piston diameter and a minimum pull rod" diameter.

SUMMARY OF THE INVENTION The present invention relates to a downhole fluid actuated pump assembly for use in lifting fluids from a fluid producing stratum associated with a well by utilizing hydraulic power or fluid from the surface of the ground which is conveyed downhole to an engine means associated with the pump assembly. The pump assembly generally is comprised of an elongated cylindrical unit having an upper end connected to the power fluid source, an outlet connected to a produced fluid flow conduit, and a pump inlet connected to or in communication with the fluid producing stratum. The engine means of the pump assembly is comprised of an upper and lower engine assembly with the pump being interposed therebetween so as to enable each engine alternately to reciprocatingly actuate the pump assembly with the connecting rods thereof being placed in compression during each power stroke of the double acting pump.

The lower engine assembly is provided with a source of power fluid by the provision of a central passageway which extends from the valve assembly, through the upper engine assembly, through the pump means, through a piston of the lower engine means, whereby fluid pressure is effected below each piston of the lower engine assembly.

Therefore, a primary object of this invention is to provide the engine of a downhole pump assembly with means for increasing the piston area thereof so that power fluid can apply an increased force in order to actuate the piston of a production pump.

Another object of this invention is to provide a downhole pump assembly with spaced apart engines which actuate a pump located therebetween.

A further object of the present invention is the provision of a multistage pump which is actuated by spaced apart multistage engines.

A still further object of the present invention is the provision of apparatus which enables a pump to be actuated by an engine with the connecting rod located therebetween being placed in compression during the power stroke.

A still further object of the present invention is the provision of apparatus which enables an improved, more powerful engine to be designed which can be used with various existing valve assemblies and production pumps in order to increase the lifting power of the entire downhole pump assembly.

The above objects are attained in accordance with the present invention by the provision of a downhole fluid actuated pump assembly having spaced apart engines associated therewith which actuates a pump located therebetween with the lower engine assembly obtaining a supply of power fluid through a central passageway located within the pistons and connecting rods of the entire assembly.

Various other objects and advantages of this invention will become readily apparent to those skilled in the art upon reading the following detailed description and by referring to the accompanying drawings.

7 BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a fragmentary part cross-sectional side view of a pump assembly made in accordance with the present invention and operatively disposed within a borehole; I

FIG. 2 is a reduced longitudinal part cross-sectional, part schematical representation of an improved fluid actuated pump assembly fabricated in accordance with the present invention;

FIGS. 3A, 3B, 3C, and 3D are enlarged broken views of a pump assembly made in accordance with the present invention, with some parts being shown in section and other parts being broken away to conserve space;

FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 3B;

FIG. 5 is a cross-sectional view taken along line 55 of FIG. 3D; and

FIG. 6 is a schematical representation of an alternate em bodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS Throughout the specification, wherever possible, like or similar numerals refer to like or similar elements.

FIG. 1 illustrates a pump assembly 10 operatively disposed within a borehole. As seen in FIG. 2, in conjunction with the remaining figures, the pump assembly preferably has a relatively constant outside diameter portion 12 with the upper extremity near numeral 14 forming a housing for the valve assembly while the lower extremity at 15 is in the form of a foot which cooperates with a seat assembly, or standing valve assembly, located downhole in a borehole, as will become more evident later on.

As seen in FIG. 2, the pump assembly includes an upper engine portion 16, a production pump 17, and a lower engine portion 18. The upper engine includes an upper working barrel, or cylinder 19, within which there is reciprocatingly received a piston 20. The upper engine assembly includes a second or lower piston 21 which is reciprocatingly received within working barrel 19'. The two pistons are interconnected by a hollow connecting rod 22 which continues in an upward direction from the first or uppermost piston as a hollow valve control rod 23. Downwardly depending from the lowermost piston there is seen a hollow connecting rod 24 which is a continuation of rod 22 and which interconnects the upper engine to a piston (not shown) of the pump. The pump can have one or more pistons and preferably is of the double action type.

A pack-off sleeve 25 sealingly receives the before mentioned hollow valve control rod therein, with the valve control rod being apertured as seen at 26 so as to enable fluid from annulus 27 to flow thereinto and towards and through the pump assembly.

A series of circumferentially disposed ports 28 and 28' communicate the longitudinal passageways 29 with the upper cylinder chambers of the upper engine assembly.

Packing gland 30 serves as an adapter and includes the illustrated passageways therein, one of which is illustrated by the numeral at 30', and provides a means by which the engine can be disassembled into its component parts, as well as sealingly separating the adjacent pistons from one another. Packing gland 31 likewise serves as an adapter and separates the uppermost pump piston from the adjacent engine piston and provides the illustrated flow passageways seen at 32' within the engine. Production ports 33 are radially spaced apart and form the production fluid outlet for the production pump. Ports 34 communicate with the illustrated passageways 131' contained within the adapter and packing gland 131.

A balance tube 35 receives the marginal free end portion of the hollow balance tube 123. Production fluid inlet 36 is adapted to be placed into communication with a fluid producing zone of the borehole so as to enable fluid to flow into chamber 37. Passageway 38 interconnects chamber 37 with the longitudinal passageways 129 which are flow connected to the production pump.

The upper engine barrel of the upper engine assembly of the engine means is divided into upper chamber 39 and lower chamber 40. The lower working barrel is divided into upper and lower chambers 41 and 42.

Looking now to the lower engine assembly of the engine means it is seen that the upper piston 120 thereof divides the upper working barrel into upper chamber 139 and lower chamber 140, while lower piston 121 divides the lower working barrel 119' into an upper chamber 141 and a lower chamber 142.

Looking again now to FIGS, 3-5, in conjunction with FIG. 2, there is seen the before mentioned valve assembly, which can take on several different forms, and the operation of which is known to those skilled in the art, and which includes the usual spent power fluid exhaust 46 and power fluid inlet 47, each of which are alternately connected to passageways 48 and 50 by the illustrated valve assembly. The fluid flow through the first passageway 48 can be traced to passageway 49, through the passageway in adapter 52, and into the longitudinally extending passageway 29. The series of radially spaced apart passageways 50 can be traced to the dash-pot plug 51, through the illustrated ports formed therein, and into the annulus 27 where the fluid is free to enter the hollow valve control rod by means of port 26.

Pistons 120 and 121 are provided with the downwardly and outwardly diverging ports 55, 56, respectively, which communicate the chambers 140, 142 with the interior of the hollow rod so as to alternately supply the lower cylinder chambers of each recited piston with power fluid or with a spent power fluid exhaust means.

FIG. 6 sets forth an alternate embodiment of the invention wherein two coacting single piston double acting engine assemblies are spaced apart from one another by a double acting production pump to provide a push-pull arrangement. As schematically disclosed in FIG. 6, the downhole pump assembly includes first passageway 223 and second passageway 227 which are alternately connected to a power fluid source and a spent power fluid exhaust by the valve means (not shown). Hollow valve control rod 224 extends through each engine, the pump, and into the balance tube as in the before described embodiment. A pack-off sleeve, such as seen in FIG. 3 maintains the two flow paths separated from each other.

Lower cylinder chambers 240 and 242 communicate with the interior of the hollow rod by means of piston passageways 255, 256. Passageway 329 is connected to upper cylinder chamber 239 by ports 228, while upper cylinder chamber 241 is connected to passageway 329 by means of a passageway 261 which extends from port 262 in the lower adapter to port 260 in the opposed adapter. The passageway 261 can be any flow conduit means by which flow is effected between chambers 241 and 329, including drilled passageways located in the pump housing.

OPERATION In operation, power fluid pumped from the surface of the earth through conduit 47 and to the engine means causes the piston or pistons of production pump 17 to reciprocate,

whereupon fluid from a fluid producing formation enters passageway 36, flows into chamber 37, passageway 38, passageways 129, and to the production pump, where produced fluid is then forced through the production pump exhaust ports and to the surface of the ground. Power fluid flowing through conduit 47 is alternately connected to passageways 50 or 48 by the action of the valve means or valve assembly in response to the position of the pilot rod 23. As power oil flows through passageways 50, for example, it continues into the annulus 27 of the pack-off sleeve, into the hollow pilot rod by means of port 26, through the central drilled passageway of piston 20, through the hollow connecting rod 22, through piston 21, through the connecting rod 24 where the fluid continues to flow through the production pump connecting rods and piston, and then on to the lower connecting rod 124.

From the lower hollow connecting rod flow continues through piston with a portion of the flow entering chamber 140 by means of drilled piston passageways 55. This provides a force for reciprocating piston 120 towards the production pump. The remainder of the flow continues through connecting rod 122 and through the piston into chamber 142 by means of piston passageways 56, so as to provide a force for reciprocating piston 12] toward the pump. Fluid pressure is also exert ed at the lower depending end of the balance tube 35 since the lower terminal end portion of rod 123 is open-ended and in communication with the last named hollow connecting rod. As pistons 120 and 121 reciprocate toward the production pump, fluid contained within chambers 139 and 141 flow out of the pump assembly by means ofthe adapter or crossover and mix with the production fluid by means of the illustrated passageways and passageway 34, 34. At the same time fluid contained within chambers 39 and 41 are exhausted through ports 28', 28, and flows along passageway 29, 49, 48, where the spent power fluid exhausts through port 46. As pistons 20, 21 reciprocate in an upward direction, chambers 40, 42 are filled with fluid by means of passageway 30' and 32.

Upon the pistons being reciprocated to .their uppermost limit, the pilot valve control rod shifts the valve assembly whereupon power fluid is now effected at passageway 48 while the exhaust ports 46 are connected to passageway 50. As power fluid flows from inlet 48, through the valve assembly, through passageway 48, 49, 29, the fluid is free to enter the upper cylinder chambers of the upper engine assembly by means of ports 28, 28'. This action forces the pistons of the upper engine in a downward direction. Fluid located within chambers 40 and 42 is forced back out of the lower cylinder chambers by means of the passageways 30, 32. At the same time spent power fluid contained within chambers 140, 142 flows back into the hollow connecting rods and back through port 50 where the spent power fluid is exhausted at 46. Fluid contained within chambers 139, 141 is expelled therefrom by means of radial passageways 130' and 131'.

Hence, it can be seen that production fluid is circulated into and out of lower cylinder chambers 40, 42 and upper cylinder chambers 139, 141, while power fluid is alternately imposed upon chambers 39, 41 and 140, 142 so as to enable the upper engine to drive the pistons towards the pump after which the lower engine drives its pistons towards the pump so as to continuously reciprocate the production pump piston in a manner which places the various connecting rods under compression at all times during a power stroke.

Accordingly, the present invention contemplates a fluid actuated pump assembly 10 which includes a valve assembly 16, an engine means comprised of engine assemblies 16 and 18, and a production pump 17. The production pump has a formation fluid inlet conduit means 36 and a produced fluid conduit means comprised of the borehole casing or a production tubing as seen at 45 in FIG. 1. A source of power fluid is connected to the valve assembly at 47. Each engine assembly includes at least one piston with the piston being reciprocatingly received within an engine cylinder or working barrel, and with each piston dividing each working barrel into an upper and lower cylinder chamber.

The valve control rod is hollow and connected between an uppermost piston and the valve assembly so as to control the fluid flow path of power fluid to and from the engine means.

A hollow connecting rod interconnects a pump piston with the piston of the upper engine while another hollow connecting rod interconnects a pump piston with a piston of the lowermost engine. The upper and lower engines are spaced apart from each other by the production pump. The various rods which interconnect the pistons can be considered a continuous rod for purposes of understanding the invention.

. What is claimed is:

l. A downhole pump assembly having means forming:

a valve assembly, an engine means, and a production pump;

said pump having means forming a production fluid inlet and a produced fluid outlet for enabling the pump to force fluid from a lower portion of a borehole towards the surface of the ground when the pump is actuated by the engine means;

said engine means including an upper engine assembly, a

lower engine assembly; said upper and lower engine assemblies being spaced apart from one another and con- I nected to said production pump;

means forming a power fluid inlet and a power fluid exhaust for said valve assembly;

.means forming a longitudinally extending central passageway which extends from said valve assembly, through said upper engine assembly, through said pump, and through at least part of said lower engine assembly for providing said lower engine assembly with a passageway through which spent power fluid and power fluid can flow to and from said valve assembly;

means forming a second flow passageway to said upper engine assembly for providing a passageway through which spent power fluid and power fluid can flow to and from said valve assembly;

means by which said upper engine assembly causes said valve assembly to alternately connect said central passageway and said second flow passageway to said power fluid inlet and said spent power fluid exhaust. 2. The downhole pump assembly of claim 1, wherein said upper engine assembly includes a pilot valve control rod;

said valve assembly has means forming a pack-off sleeve; said valve control rod being received within said sleeve;

means forming a flow passageway which extends from the interior of said pack-off sleeve and into said valve control rod to provide a portion of said central passageway.

3. The downhole pump assembly of claim 1 wherein said upper engine assembly includes a piston, a cylinder, said piston being reciprocatingly received within said cylinder and dividing said cylinder into an upper and lower cylinder chamber;

said lower engine assembly includes a piston, a cylinder,

with the last said piston being reciprocatingly received within the last said cylinder to form an upper and lower cylinder chamber;

said second flow passageway being connected to the upper cylinder chamber of said upper engine assembly;

said central passageway being connected to the lower cylinder chamber of said lower engine assembly, whereby:

said piston of said upper engine assembly strokes said pump in a downward direction while said piston of said lower engine assembly strokes said pump in an upward direction.

4. The downhole pump of claim 3, and further including means forming ports into said lower cylinder chamber of said upper engine assembly; means forming ports into said upper cylinder chamber of said lower engine assembly, whereby:

the last recited cylinder chambers exhaust and intake production fluid as the engine means strokes the production pump.

5. The downhole pump assembly of claim 3 wherein each said piston includes a connecting rod connected to said pump;

said central passageway includes means forming a flow path through said piston of said upper engine assembly, through the connecting rod connected thereto, from said pump into the connecting rod connected to said piston of said lower engine assembly, and through said piston of said lower engine assembly, into the lower chamber thereof.

6. A fluid actuated pump assembly which includes a valve assembly, an engine means, and a production pump, with the production pump having a formation fluid inlet conduit means and a produced fluid outlet conduit means flow connected thereto; means for connecting a source of power fluid to the valve assembly; the improvement comprising:

said engine means including a first and second piston, a first and second engine cylinder, said first and second piston,

respectively, being reciprocatingly received within said first and second engine cylinder, respectively; each said piston dividing each said engine cylinder into an upper cylinder chamber and a lower cylinder chamber; said first piston and said first engine cylinder forming an upper engine assembly; said second piston and said second engine cylinder forming a lower engine assembly;

a valve control rod having a flow passageway therein, means connecting said control rod between said first piston and the valve assembly for enabling the valve assembly to control the flow of power fluid to and from the valve assembly and the engine means;

a first connecting rod connected between said first piston and the production pump, a second connecting rod connected between said second piston and the production pump; said first and second engine pistons being spaced apart from each other by the production pump;

means forming a first flow passageway which extends from said valve assembly to one said cylinder chamber of the uppermost engine for conducting power fluid and spent power fluid to and from said cylinder chamber;

means forming a second flow passageway which extends from said valve assembly, through said valve control rod, through the piston of said upper engine means, through the upper connecting rod, through the pump, through the lower connecting rod, through the lower engine piston, and to the lower cylinder chamber of the lower engine assembly; whereby:

said valve assembly conducts power fluid flow to the upper engine while spent power fluid is returned from the lower engine and vice versa, to thereby enable one engine assembly to stroke the pump in one direction while the other engine assembly strokes the pump in another direction.

7. The improvement of claim 6, and further including a pack-off sleeve connected to said valve assembly with said valve control rod being reciprocatingly received therein;

said flow passageway includes a passageway which extends from said valve assembly, into the interior of said pack-off sleeve, and into said control rod.

8. The improvement of claim 6, and further including a second upper engine assembly interposed between the pump and the upper engine assembly, and a second lower engine assembly interposed between the pump and the lower engine assembly.

9. The improvement of claim 8, wherein the production pump is a multistage pump.

10. The improvement of claim 6 wherein there is further in- 'cluded means forming ports into said lower cylinder chamber of said upper engine assembly; means forming ports into said upper cylinder chamber of said lower engine assembly, whereby:

the last recited cylinder chambers exhaust and intake production fluid as the engine means reciprocates the production pump. 

1. A downhole pump assembly having means forming: a valve assembly, an engine means, and a production pump; said pump having means forming a production fluid inlet and a produced fluid outlet for enabling the pump to force fluid from a lower portion of a borehole towards the surface of the ground when the pump is actuated by the engine means; said engine means including an upper engine assembly, a lower engine assembly; said upper and lower engine assemblies being spaced apart from one another and connected to said production pump; means forming a power fluid inlet and a power fluid exhaust for said valve assembly; means forming a longitudinally extending central passageway which extends from said valve assembly, through said upper engine assembly, through said pump, and through at least part of said lower engine assembly for providing said lower engine assembly with a passageway through which spent power fluid and power fluid can flow to and from said valve assembly; means forming a second flow passageway to said upper engine assembly for providing a passageway through which spent power fluid and power fluid can flow to and from said valve assembly; means by which said upper engine assembly causes said valve assembly to alternately connect said central passageway and said second flow passageway to said power fluid inlet and said spent power fluid exhaust.
 2. The downhole pump assembly of claim 1, wherein said upper engine assembly includes a pilot valve control rod; said valve assembly has means forming a pack-off sleeve; said valve control rod being received within said sleeve; means forming a flow passageway which extends from the interior of said pack-off sleeve and into said valve control rod to provide a portion of said central passageway.
 3. The downhole pump assembly of claim 1 wherein said upper engine assembly includes a piston, a cylinder, said piston being reciprocatingly received within said cylinder and dividing said cylinder into an upper and lower cylinder chamber; said lower engine assembly includes a piston, a cylinder, with the last said piston being reciprocatingly received within the last said cylinder to form an upper and lower cyliNder chamber; said second flow passageway being connected to the upper cylinder chamber of said upper engine assembly; said central passageway being connected to the lower cylinder chamber of said lower engine assembly, whereby: said piston of said upper engine assembly strokes said pump in a downward direction while said piston of said lower engine assembly strokes said pump in an upward direction.
 4. The downhole pump of claim 3, and further including means forming ports into said lower cylinder chamber of said upper engine assembly; means forming ports into said upper cylinder chamber of said lower engine assembly, whereby: the last recited cylinder chambers exhaust and intake production fluid as the engine means strokes the production pump.
 5. The downhole pump assembly of claim 3 wherein each said piston includes a connecting rod connected to said pump; said central passageway includes means forming a flow path through said piston of said upper engine assembly, through the connecting rod connected thereto, from said pump into the connecting rod connected to said piston of said lower engine assembly, and through said piston of said lower engine assembly, into the lower chamber thereof.
 6. A fluid actuated pump assembly which includes a valve assembly, an engine means, and a production pump, with the production pump having a formation fluid inlet conduit means and a produced fluid outlet conduit means flow connected thereto; means for connecting a source of power fluid to the valve assembly; the improvement comprising: said engine means including a first and second piston, a first and second engine cylinder, said first and second piston, respectively, being reciprocatingly received within said first and second engine cylinder, respectively; each said piston dividing each said engine cylinder into an upper cylinder chamber and a lower cylinder chamber; said first piston and said first engine cylinder forming an upper engine assembly; said second piston and said second engine cylinder forming a lower engine assembly; a valve control rod having a flow passageway therein, means connecting said control rod between said first piston and the valve assembly for enabling the valve assembly to control the flow of power fluid to and from the valve assembly and the engine means; a first connecting rod connected between said first piston and the production pump, a second connecting rod connected between said second piston and the production pump; said first and second engine pistons being spaced apart from each other by the production pump; means forming a first flow passageway which extends from said valve assembly to one said cylinder chamber of the uppermost engine for conducting power fluid and spent power fluid to and from said cylinder chamber; means forming a second flow passageway which extends from said valve assembly, through said valve control rod, through the piston of said upper engine means, through the upper connecting rod, through the pump, through the lower connecting rod, through the lower engine piston, and to the lower cylinder chamber of the lower engine assembly; whereby: said valve assembly conducts power fluid flow to the upper engine while spent power fluid is returned from the lower engine and vice versa, to thereby enable one engine assembly to stroke the pump in one direction while the other engine assembly strokes the pump in another direction.
 7. The improvement of claim 6, and further including a pack-off sleeve connected to said valve assembly with said valve control rod being reciprocatingly received therein; said flow passageway includes a passageway which extends from said valve assembly, into the interior of said pack-off sleeve, and into said control rod.
 8. The improvement of claim 6, and further including a second upper engine assembly interposed between the pump and the upper engine assembly, and a second lower engine assembly interposed between the pump and the lower engine assEmbly.
 9. The improvement of claim 8, wherein the production pump is a multistage pump.
 10. The improvement of claim 6 wherein there is further included means forming ports into said lower cylinder chamber of said upper engine assembly; means forming ports into said upper cylinder chamber of said lower engine assembly, whereby: the last recited cylinder chambers exhaust and intake production fluid as the engine means reciprocates the production pump. 